Boiler feed-water treatment



Jam. 6, 1931. P. M.'CONTAN'I; I 1,738,149

BOILER FEED WATER TREATMENT Filed 0 t. 11, 1928 2 Sheets-Sheet 1 WINVENTOR.

4 ATTORNEY.

Jan. 6, 1931. P. M. coNTANT 1,788,149

BOILER FEED WATER TREATMENT Filed Oct. 11, 1928 2 Sheets-Sheet 2 Q IYINVENTOIR.

4/5 ATTORNEY;

Patented Jan. 6, 1931.

v UNITED STATES ATENT- OFFICE,

PETER 1a; com'm'r, or new YORK, N. in,

assienoa 'ro uncium warm: some-Nun,

CORIORAT ION, OF NEW YORK, N. Y., A CORPORATION 01 NEW YORK BOILERFEED-WATER TREATMENT Application filed October 11, 1928.. Serial No.811,789.

The present inventionrelates to processes for treating boiler feed waterto prevent and to check embrittlement of boiler materials.

Feed waters containing sodium bicarbonate produce a strongly alkalinecondition in the boilers upon concentration through evaporation, thehigh temperatures driving off carbon dioxide and thereby reducing thebicarbonate to normal carbonate. The normal n carbonate is thenpartially split up within the boiler into sodium hydroxide. The fprmedsodium hydroxide, in the absence of a suflicient amount of sodiumsulphate in the boiler water, has a very detrimental efi'ect Q on thestructural material of the steam boiler.

. It is an object of the present invention to prevent such detrimentalefiect by increasing the amount of sodium sulphate and decreasing theamount of sodium carbonate in the boiler feed water through ropertreatment.

Further ob'ects and a vanta es will be apparent in t e following detaied description taken in conjunction with the accompanying drawings,wherein:

Fig. 1 is an elevation of a ty ical installationcomprising a; boiler,feetreatment tank, and

Fig. 2 is a sectional elevationofthe treatment tank showing details ofconstruction and arrangement. 7 I

In the figures, the boiler A receives treated feed water from thetreatment tank B through the feed conduit 4 and the boiler feed pump.

A continuous return'from the boiler A, or from each boiler, in a batteryof boilers, is led from the blow-ofi pipe 9 through valvecontrolledpipev'l, equipped with sampling cock-8, into the return pipe10 which discharges directly into the treatment tank B 4 within acentral reaction chamber 3. The hot Boiler return heats and reacts withthe mixture of descending untreated make-up water received through pi e2 and the ferrous sulphate solution supp ed from chemical tank C throughthe valve-controlled drip feeder pump, and

into normal carbonate.-

1. The untreated make-up water may, if desired, first pass through a.preheater D having a steam inlet 15, a vent 16 and a conduit 6 leadinginto the treatment tank B.

Within the reaction chamber 3 the sodium bicarbonate present in the rawwater, the sodium hydroxide present in the boiler return, and theferrous sulphate fed from the chemical tank, react to form sodiumsulphate and insoluble ferrous carbonate,-and the sodium carbonatepresent in the boiler return water also reacts with the ferrous sulphateto also form sodium sulphate and insoluble ferrous carbonate,inaccordance with the following equatipns:

NaHCO +NaOH+FeSO Na SO FeCO +H O Na cO FeSO Na SO FQOOa In other words,by supplying one molecule pf ferrous sulphate for any two molecules ofsodium bicarbonate in the make-up water (potentially equivalent to onemolecule of sodium carbonate in the boiler), one molecule of sodiumsulphate is formed, and a similar conversion is brought about in thereaction of the ferrous sulphate with the sodium' carbonate in theboiler return. Since the ferrous carbonate-is insoluble, the result ofthe reaction does not change the number of 7 molecules of soluble saltsin the feed water. It is desirable to keep the dissolved solids in thefeed water as low as possible in order to avoid high concentrationswithin the boilers.

. A positive reaction of the ferrous sulphate on the sodium bicarbonatein the make-up water depends on the-conversion of the sodium bicarbonateby 'the sodium hydroxide If the reaction is not completed, however,,thesodium carbonate is returned from the boiler as normal carbonate, underthe influence'of the boiler conditions; and the process thereforeaffords a simple means for establishing any desired predetermined ratiobetween sodium carbonate and sodium sulphate in the boiler water.

Thus, assuming a make-up water having the following composition,expressed in parts per million:

Ca 57 Mg 26 Na 32 Cl v 2 H 365 S0. 5

A ,the boiler water will show a ratio of sodium sulphate to soda (methylorange) alkalinity of 7 .4 to 65.3 if no treatment should be ap-' plied.If it is desired to chan e this ratio to the proportion 3.5 to 1,suflic'ent ferrous sulphate is added to the water to convert 46.0 p. p.m. of sodium carbonate into sodium sulphate, thereby creating 46x142/106 or 61.6 p. p. m. of sodium sulphate.

I claim:

. 1. A method of treating boiler feed water containing sodiumbicarbonate, comprising subjecting the sodium bicarbonate to heat toform sodium carbonate and sodium hydroxide, and reacting the formedsodium c'artinuously blowing-ofl 'boiler water containing sodiumcarbonate and sodium hydroxide, and reacting the blow-off water withadditional feed water containing sodium bicarbonate and with ferroussulphaterto form sodium sulphate and ferrous carbonate.

In testimony whereof I aflix mv signature.

PETER M. CONTANT.

bonate and sodium hydroxide and additional sodium bicarbonate withferrous sulphate to form sodium sulphate and ferrous carbonate.

2. A method of treating boiler feed water containin sodium bicarbonate,comprising treating t e sodium bicarbonate to form sodium carbonate andsodium hydroxide, and reacting the formed sodium carbonate and sodiumhydroxide and additional sodium bicarbonate with ferrous sulphate toform sodium sulphate and ferrous carbonate.

3. A method of treating boiler feed water containing sodium bicarbonate,comprising subjecting water containing sodium bicar bonate to heat toform sodium carbonate and sodium hydroxide, and'adding the formed sodiumcarbonate and sodium hydroxide together with regulated quantities offerrous sulphate to the feed water to establish a desired ratio ofsodium sulphate to sodium hydroxide in the boiler.

4. A method of treating boiler feed Water containing sodium bicarbonate,comprising subjecting water containing sodium bicarbonate to heat toform sodium carbonate and sodium hydroxide, and addin the formed sodiumcarbonate and sodium ydroxide together with regulated quantities offerrous sulphate to the feed water to establish a desired ratio ofsodium sulphate to soda alka I linity in the boiler.

5. A method of controlling the composition of boiler water when usingfeed water containing sodium bicarbonate, comprising subjecting feedwater to the heat of the boiler to form sodium carbonate and sodium.-hydroxide, and treating additional feed water containing sodiumbicarbonate with the

